A new catheter for tumor targeting with radioactive microspheres in representative hepatic artery systems. Part I: impact of catheter presence on local blood flow and microsphere delivery.

Building on previous studies in which the transport and targeting of (90)Y microspheres for liver tumor treatment were numerically analyzed based on medical data sets, this two-part paper discusses the influence of an anchored, radially adjustable catheter on local blood flow and microsphere delivery in an idealized hepatic artery system (Part I). In Part II a patient-inspired case study with necessary conditions for optimal targeting of radioactive microspheres (i.e., yttrium 90) onto liver tumors is presented. A new concept of optimal catheter positioning is introduced for selective targeting of two daughter-vessel exits potentially connected to liver tumors. Assuming laminar flow in rigid blood vessels with an anchored catheter in three controlled positions, the transient three-dimensional (3D) transport phenomena were simulated employing user-enhanced engineering software. The catheter position as well as injection speed and delivery function may influence fluid flow and particle transport. Although the local influences of the catheter may not be negligible, unique cross-sectional particle release zones exist, with which selectively the new controlled targeting methodology would allow optimal microsphere delivery. The insight gained from this analysis paves the way for improved design and testing of a smart microcatheter (SMC) system as well as new investigations leading to even more successful treatment with (90)Y microspheres or combined internal radiation and chemotherapy.